This invention relates to novel apparatus for producing controlled motion of one mass relative to another mass.
An example of a use for such apparatus is as test apparatus to simulate the vibrations that various kinds of electrical, electronic, mechanical or hydraulic equipment may actually experience to ensure that the equipment being tested will meet its design specifications. For instance, equipment designed for use in a missile must perform its intended functions within the range of frequencies and amplitudes of motion to which the equipment is subjected during the actual missile flight. To assure operational reliability and performance of such equipment, the equipment must be tested before actual use on test apparatus capable of simulating the vibrations expected to be encountered.
Test equipment currently available generally are capable of simulating various vibrational frequencies and amplitudes with one or two degrees of freedom, i.e., along one or two axes of an XYZ coordinate system. Often, even if two axes are used, the motions are not independent. Thus testing such equipment for vibration resistance along all three axes, requires two or three separate tests with the equipment under test oriented in the two or three different directions. Aside from the additional time expended, this is clearly a compromise relative to the vibrational conditions actually experienced by the equipment, which will in actual use be simultaneously subject to vibration in all three directions.
More recent designs of test equipment provide two or three degrees of freedom. However, such designs employ multiple actuators operating in each of several of the three different directions. As a result, the equipment is expensive and cumbersome. Moreover, the multiple actuators extending in each direction must be cross-coupled or compensated to maintain dimensional stability of the equipment support. Still further the actuators used are relatively short. As a result, cross-coupling or compensation of the actuators extending in the different directions becomes necessary for the same reason. This adds to the cost and complexity of the equipment. No apparatus to the best of my knowledge is available that provides in excess of three degrees of freedom.
A principal object of the invention is simplified apparatus capable of generating controlled motion with at least three degrees of freedom.
A further object of the invention is apparatus capable of providing controlled motion with from three to six degrees of freedom.
Another object of the invention is a novel actuator for use in controlled motion apparatus.